1. Field of the Invention
The present invention relates to air pressure valves and gauges and more particularly to a tire valve having a pressure gauge combined therewithin.
2. Description of the Prior Art
Present tire valve stems are designed simply to house a valve to regulate the flow of air into and out of tires. In order to measure the pneumatic pressure within a tire, a separate tire gauge must be used, and this involves much time and inconvenience. Without properly inflated tires, a motor vehicle's handling and braking ability is greatly reduced, while the rate of gasoline consumption and tire wear is increased.
A tire valve stem with a built-in pressure indicator will eliminate the need to carry a separate tire gauge to measure the pneumatic pressure of a tire. Reading the air pressure of a tire can be accomplished at a glance. There is no need to unfasten a valve cap, or to insert a tire gauge into the nozzle. The present design configuration is arranged in a manner which will allow for the constant monitoring of pneumatic tire pressure. It is intended to aid in the promotion of traffic and air safety while reducing the rate of unnecessary gasoline consumption and tire wear.
The practical incorporation of an air pressure gauge within a tire valve stem has long been attempted. Prior art patents such as U.S. Pat. Nos. 1,400,848, Pressure Gage, issued Dec. 20, 1921 to T. W. Anderson, 1,606,740, Tire Stem Pressure Gauge, issued Nov. 16, 1926 to A. Badowski, and 3,246,679, Combination Valve and Pressure Gauge, issued Apr. 19, 1966 to E. J. Stealy, exemplify significant prior art. In each of the above-mentioned patents, a pressure gauge is incorporated within the dimensional confines of a tire valve stem.
Anderson teaches a pressure gauge incorporated within a valve stem (see FIG. 2), having an elastic diaphragm G which, per column 1, line 52, may include other pressure responsive means. The diaphragm is restrained by a calibrated spring K, and a rod L extends through a hole in a support head W to terminate in a rack N. The rack N meshes with a pinion O residing on a shaft P which also holds a beveled gear Q which meshes with a beveled gear R disposed on a rotatable shaft S. The rotatable shaft S contains a rotary pressure indicator M having numerals disposed thereon which are viewed through a window T. An air channel C is disposed in the wall of the tire stem to transmit air from the check valve B to the tire. It is therefore to be appreciated that Anderson teaches a relevant but complicated mechanism.
Badowski, U.S. Pat. No. 1,606,740, teaches a tire stem pressure gauge device which includes a bellows-type extensible member 17 which expands in its length within the tire stem depending upon the tire pressure. The bellows 17 is apparently engaged to a vertically-extending pressure indicator 14 which displays tire pressure as a direct function of the extension of the bellows-type member 17. The Badowski device is designed to accommodate tire stems differing in design from those currently available, and it is not readily apparent how this design could be accommodated within tire stems currently available.
Stealy, U.S. Pat. No. 3,246,679, teaches a combination valve and pressure gauge which is incorporated within the conically-shaped tire valve stem designs currently utilized. In Stealy, a pressure-sensitive elastic chamber 62 communicates through bore 60 with the inner tire air pressure. The chamber 62 expands against a calibrated spring 64 and a rod 54 projects through the upward portions of the tire stem and terminates in an indicator 55. Thus, the longitudinal extension of the elastic chamber 62 is directly reflected in the longitudinal extension of the indicator 55. Tire pressure markings are disposed upon a clear tire valve cap 15 to correlate with the outward extension of the indicator 55. Thus, a drawback to the Stealy device is that the tire cap 15 must be fully screwed onto the tire valve nozzle in order to determine the pressure within the tire. A user, upon inflating the tire, might have to screw the cap onto the nozzle several times to achieve the desired pressure.
Other patents of interest are U.S. Pat. Nos. 1,268,467, Pressure Connection and Gage, issued to C. I. Jacobson and A. L. Fowler, June 4, 1918; 4,058,099, Arrangement for Monitoring Pneumatic Tire Inflation Pressure, issued to Etter-Felix on Nov. 15, 1977; 4,244,214, Visual Tire Valve, issued to William F. Curran on Jan. 13, 1981. Jacobson, 1,268,467, depicts a complicated device that is not readily understandable but appears to be less relevant than Anderson, Badowski or Stealy. Etter-Felix, U.S. Pat. No. 4,058,009, teaches a device which is not readily substitutable for a tire valve stem, and does not appear to be as pertinent as Anderson, Badowski or Stealy. Curran, U.S. Pat. No. 4,244,214, teaches a tire valve for mounting over a valve stem and is therefore not a device designed to be incorporated within a valve stem. Curran includes a window which depicts one of the three different colored bands to indicate over-inflation, proper inflation and under-inflation. A calibrated spring which resists movement of an air flow control rod is utilized to control which color is shown in the window.